Laser etches the shape of cross-section into metal powder and heats it so it solidifies and creates a solid layer

More powder is spread to create the next layer and so on until the 3D object is created

By leaving one non-solid layer in between, interlocking structures can be created

“To build a [fusion reactor], like Iter, you somehow have to take the heat of the Sun and put it in a metal box.

“3,000C is as hot as you can imagine for engineering.

“If we can get 3D metal printing to work, we are well on the way to commercial nuclear fusion.”

Additive manufacturing with metal is not new; General Electric, for example, has used the technique to make fuel injectors for one of its aircraft engines. China claims to be using 3D printing to manufacture load-bearing components in aircraft.